RF Channel Reconfiguration xApp

July 30, 2026 · View on GitHub

Overview

The RF Channel Reconfiguration xApp uses the E2 Service Model (E2SM) Cell Configuration and Control (CCC) O-RAN service model to dynamically adjust antenna port activation and transmission power at the simulated gNB. By reacting to observed network conditions, the xApp enables intelligent energy saving and performance optimization through RF-layer reconfiguration — without any manual intervention.

Attribute	Value
Service Model	CCC v06.00 (Cell Configuration and Control)
Scenario File	`scratch/RF_Reconfiguration.cc`
xApp Binary	`rf_reconfiguration_xapp`
FlexRIC Branch	`OIE-add-CCC`
Reporting Used	KPM v3.00

How It Works

┌──────────────────────────────────────────────────────────────────┐
│                          near-RT RIC                             │
│                                                                  │
│  KPM CU-UP Indication ──► RF Reconfig xApp ──► CCC Control      │
│  (power, throughput,        (decision logic)    (port ON/OFF,    │
│   ports, energy)                                 power level)    │
└──────────▲──────────────────────────────────────────┬───────────┘
           │ E2 Interface                              │ E2 Interface
           │                                           ▼
┌────────────────────────────────────────────────────────────────┐
│                      ns-3 Simulation (5G-LENA)                 │
│                                                                │
│   NrGnbNetDevice ── CCC port/power model ── UEs               │
└────────────────────────────────────────────────────────────────┘

Step-by-step operation:

The xApp subscribes to KPM CU-UP indication messages from the gNB.
Each indication carries per-cell metrics including:
- UE downlink throughput
- Average and instantaneous transmit power
- Active antenna port configuration (ports ON / OFF count)
- Energy consumption samples
The xApp evaluates the metrics and sends a CCC Control message instructing the gNB to:
- Increase or decrease the number of active antenna ports.
- Adjust the transmit power scaling factor per port.
The gNB reconfigures its RF layer and reflects the new state in subsequent indication messages.
The closed loop repeats for the duration of the simulation.

Dashboard

The RF Channel Reconfiguration tab in RIC-TaaP Studio provides a live view of the xApp operation:

RF Channel Reconfiguration Dashboard

Panel	Description
UE DL Throughput	Per-UE downlink throughput over time (Mbps)
Network Average Power	Average gNB transmit power (W)
Indication Message Content	Raw KPM indication fields received from the gNB
Control Message Content	CCC control fields sent by the xApp
Power & Energy Consumption	Per-cell power before and after reconfiguration

Prerequisites

Before running this xApp, make sure the following are in place:

FlexRIC built from the OIE-add-CCC branch (see build instructions below).
ns-O-RAN-flexric built (see README §9.4).
RIC-TaaP Studio deployed (see README §9.5).

Build FlexRIC with the CCC branch:

cd /path/to/flexric
git checkout OIE-add-CCC
cd build
make -j8
sudo make install

Running with RIC-TaaP Studio (Recommended)

Step 1 — Start the near-RT RIC

cd /path/to/flexric/build/examples/ric/
./nearRT-RIC

Step 2 — Open RIC-TaaP Studio

Open your browser at http://127.0.0.1:8000.

Step 3 — Connect to FlexRIC

Click Connect to FlexRIC on the homepage.

Step 4 — Select and configure the scenario

Click Show Form.
From the scenario list, select RF_Reconfiguration.cc.
Click Start. The simulation will begin and cells/UEs will appear on the grid.

Step 5 — Launch the RF Reconfiguration xApp

cd /path/to/flexric/build/examples/xApp/c/orange/
./rf_reconfiguration_xapp

Step 6 — Observe results

Click the RF Channel Reconfiguration tab in RIC-TaaP Studio to monitor the live dashboard (see Dashboard section above).

Step 7 — Stop the simulation

Click Stop in the Show Form window.

Running from Terminal

Open three separate terminals:

# Terminal 1 — near-RT RIC
cd /path/to/flexric/build/examples/ric/
./nearRT-RIC

# Terminal 2 — ns-3 simulation
cd /path/to/mmwave-LENA-oran
./ns3 run scratch/RF_Reconfiguration.cc

# Terminal 3 — RF Reconfiguration xApp
cd /path/to/flexric/build/examples/xApp/c/orange/
./rf_reconfiguration_xapp

CCC Service Model — Technical Details

The CCC v06.00 service model was implemented from scratch as part of this project. The key components in the 5G-LENA layer are:

Component	File	Function
Port power control	`model/nr-gnb-net-device.cc`	`GetPortPower()`, `SetPortPower()`, `GetPortPowerScaling()`
Port state reporting	`model/nr-gnb-net-device.cc`	`GetPortPower()` → `AddPHYGnbConfiguration(numActiveUes, cellId, portsOn, portsOff)`
Power sampling	`model/nr-gnb-net-device.cc`	`SampleTransmitPower()` — runs every 100 ms after `DoInitialize()`
E2 reporting period	`model/nr-gnb-net-device.cc`	Attribute `E2Periodicity` on `NrGnbNetDevice` (seconds)
CSV logging	`model/nr-gnb-net-device.cc`	`BuildGUICuUp()` → `nr-cu-up-cell-<id>.txt`; attribute `EnableE2FileLogging`

Power model details:

Metric	Description
Instantaneous power	Computed from PRB utilization and antenna activity model
Baseline power	Sampled before xApp execution for comparison
xApp power	Sampled after reconfiguration
Savings (%)	`(baseline − xApp) / baseline × 100` derived from sampling windows